1. Field of the Invention
The present invention relates to an air conditioner for vehicle use in which thermal comfort is improved in the neighborhood of side windows in a vehicle passenger compartment.
2. Description of the Related Art
Recently, there has been an increasing demand for thermal comfort in a vehicle passenger compartment. For example, in the case of sunshine incident from the side of the vehicle into the vehicle passenger compartment, the thermal environment in the right portion in the vehicle passenger compartment and that in the left portion are different from each other. Therefore, it is preferable that the blowout air temperature of air blown out from an air conditioner to the right portion in the vehicle passenger compartment is different from the blowout air temperature of air blown out from the air conditioner to the left portion.
Therefore, in some deluxe cars, a right and left independent temperature control type air conditioner is employed in which the temperature in the right portion of the vehicle passenger compartment and the temperature in the left portion are controlled independently from each other. Recently, there is a tendency for more cars employ this right and left independent temperature control type air conditioner. According to this type of air conditioner, the temperature of air blown out into the right region in the vehicle passenger compartment and that of air blown out into the left region can be independently controlled to temperatures suitable for the environments in the right and the left region.
Another prior art, which is disclosed in the official gazette of Japanese Unexamined Patent Publication No. 58-211905, describes an air conditioner for vehicle use in which a hot air blowout duct extending in the longitudinal direction of a vehicle is provided on the door body portion of the vehicle, and a hot air is blown out from this hot air blowout duct toward the knee and waist of a passenger.
However, it has been made clear that even if the former, that is, a right and left independent temperature control type air conditioner is employed, it is impossible to obtain a sufficiently high thermal comfort in the neighborhood of side windows in the vehicle passenger compartment.
FIG. 25A is a view for explaining an air-conditioned state in the neighborhood of side windows in a vehicle passenger compartment in summer. In FIG. 25A, the state is shown in which sunshine A is incident on the right portion of the upper half body of passenger B through side windows 13a, 14a of the vehicle doors 13, 14. At this time, cold air C is blown out from a center face blowout port (not shown in the drawing), which is arranged close to the central portion of the instrument panel of the vehicle, to the upper half body of the passenger, and cold air D is blown out from a side face blowout port (not shown in the drawing), which is arranged in a portion close to each end portion of the instrument panel of the vehicle in the lateral direction, to the upper half body of the passenger.
At this time, when the blowout air temperatures of cold air C and D are adjusted according to a quantity of the sunshine, it is possible to air-condition the right and left regions in the vehicle passenger compartment while an intensity of air-conditioning is being well balanced with a change in the quantity of the sunshine. However, the sunshine is directly incident on the right portion of the upper half of the body of passenger A which is located on the left in FIG. 25A, and the sunshine is not incident on the left portion of the upper half of the body of passenger A which is located on the right in FIG. 25A. However, cold air C and D are blown out while the temperature of cold air C and that of cold air D are controlled to the same temperature. Therefore, passenger A feels hot in the left portion of the upper half body. On the contrary, passenger A feels cold in the right portion of the upper half body.
That is, it is impossible to give an appropriate thermal feeling to the right and left upper half portions of passenger A according to the intensity of the sunshine. As a result, it is impossible to provide a sufficiently high thermal comfort at the time of air conditioning.
Next, FIG. 25B is a view for explaining a heated state in the neighborhood of side windows in the vehicle passenger compartment in winter. Hot air I is blown out from a foot blowout port, which is arranged in a lower portion of the instrument panel of the vehicle, to the foot portion of passenger A. Therefore, the foot portion of passenger A can be heated.
In this connection, in winter, these side windows 13a, 14a are cooled by the outside air of low temperature. Therefore, the temperatures of these side windows 13a, 14a are low. Accordingly, air in the vehicle passenger compartment in the neighborhood of these side windows 13a, 14a is cooled, and the temperature of the air is low. This air of low temperature is directed downward as shown by arrow L because a difference of density exists between this air of low temperature and hot air I blowing to the foot portion. Accordingly, passenger A tends to feel cold in the right shoulder and the right knee. It is impossible to solve these problems, in which passenger A feels cold in the right shoulder and the right knee, only by blowing out a hot air to the foot portion. Therefore, the thermal comfort is insufficient at the time of heating.
According to the latter prior art described before, only the feeling of heating of the knee and waist of the passenger can be improved. It is impossible to solve the problems in which passenger A feels hot in the upper half body by sunshine A at the time of air conditioning shown in FIG. 25A. It is also impossible to solve the problems in which passenger A feels cold in the shoulder by the cold air in the neighborhood of the side windows 13a, 14a at the time of heating shown in FIG. 25B. Therefore, it is impossible to provide a sufficiently high thermal comfort.